Glycocyamidine derivatives

ABSTRACT

The glycocyamidine derivatives of the present invention are represented by the following formula (I): ##STR1## wherein R 1 , R 2  and R 3 , which may be the same or different, is hydrogen or a lower alkyl group, preferably a straight or branched alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl, propyl or isopropyl, and R represents hydrogen or an acetyl group. 
     which are useful as test reagents for diagnosis of renal failure.

BACKGROUND OF THE INVENTION

The present invention relates to novel glycocyamidine derivatives andsalts thereof which are useful as test reagents for diagnosis of renalfailure.

In renal failure such as uremia, chronic nephritis or urinaryobstruction, lowering of glomerular filtration rate caused by functionaldecrease of kidney is observed. The test measuring glomerular filtrationrate is usually used to diagnose the renal failure. In particular, thecreatinine clearance test based on blood and urinal creatinine level isoften used.

As a result of investigations for metabolism of creatinine and the likein renal failure, the inventors of the present invention isolated andidentified a novel compound from urine of patients suffering from renalfailure. It was observed that this compound was increasingly producedand accumulated in the body at the diseased state such as renal failure.Therefore, it can be easy to make a diagnosis of various renal failuresbased on the existence and the amount of the compound in the fluid suchas serum or cerebrospinal fluid and the urine.

SUMMARY OF THE INVENTION

An object of the present invention is to provide novel glycocyamidinederivatives which are useful as test reagents for diagnosis of renalfailure.

DETAILED DESCRIPTION OF THE INVENTION

The glycocyamidine derivatives of the present invention are representedby the following formula (I). ##STR2##

In the above formula (I), R₁, R₂ and R₃, which may be the same ordifferent, is hydrogen or a lower alkyl group, preferably a straight orbranched alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl,propyl or isopropyl. R represents hydrogen or an acetyl group.

The compounds of the above formula (I) can be represented by thefollowing formula (II) or (III) as tautomeric isomers. ##STR3## whereineach of R₁, R₂, R₃ and R has the same meaning as in the formula (I).

The glycocyamidine derivatives of the present invention includepharmaceutically acceptable salts of the compounds having above formula(I), for example, salts with alkali metal such as sodium or potassium,with alkaline-earth metal such as magnesium, calcium or barium, or withother metals such as aluminum, or salts as acid addition with an acidsuch as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid,formic acid, acetic acid, citric acid or lactic acid, or salts with anorganic base such as ammonia or the like. These salts can be preparedfrom free glycocyamidine derivatives or other salts of these derivativesby a known method.

When optional isomers exist in the compounds of the invention, thepresent invention includes any of the DL-, D- and L-isomers.

The glycocyamidine derivatives of the present invention can be preparedas follows.

For example, the compounds represented by the following formula (IV) canbe used as starting materials. ##STR4## wherein each of R₁, R₂ and R₃has the same meaning as in the formula (I).

The 1-position, 3-position and/or an amino group of 2-position of thecompound of the formula (IV) are protected by a conventionalamino-protecting group such as t-butoxycarbonyl group, and then anacetoxy group is introduced into the 5-position of the compound bytreatment with an oxidizing agent such as lead tetraacetate. Theamino-protecting group is removed by a conventional method, for example,t-butoxycarbonyl group is removed by using trifluoroacetic acid, andthen the acetoxy group is reduced in usual way to give5-hydroxyglycocyamidine derivatives.

The resulting compounds of the present invention can be purified byknown methods such as distillation chromatography and recrystallization.Identification is established through melting point (m.p.), elementalanalysis, IR, NMR, UV, mass spectrum, etc.

EXAMPLE

The following examples, which are illustrative only and not intended tolimit the scope of the invention, describe the preparation of thecompounds of the present invention.

EXAMPLE 1

(1) 10 g of 1-methylglycocyamidine and 29 g of t-butoxycarbonylanhydride were dissolved in 300 ml of dimethylformamide, and stirredovernight at 60° C. The solution was concentrated to dryness and 100 mlof water was added to the residue. The resulting product was extractedby 100 ml of acetic acid twice. The organic layer was concentrated todryness under reduced pressure. The residue was purified by silica gelcolumn chromatography (70% ethylacetate/hexane) to give 12.6 g of N²-t-butoxycarbonyl-1-methylglycocyamidine in the form of pale yellowneedle crystals.

m.p.: 109-110 ° C.

In the same manner, the following compounds were obtained.

N² -t-butoxycarbonyl-3-methylglycocyamidine

3-t-butoxycarbonyl-N² -methylglycocyamidine

1,N² -di-t-butoxycarbonylglycocyamidine

(2) 11.6 g of N² -t-butoxycarbonyl-1methylglycocyamidine and 36.2 g oflead tetraacetate were dissolved in 300 ml of dried benzene. Thesolution was refluxed with heating for 90 minutes and then cooled toroom temperature. A small amount of water was added thereto. Afterremoving the resulting precipitate and aqueous layer, the organic layerwas dried over sodium sulfate anhydride. The resulting solution passedthrough a short column of silica gel and concentrated under reducedpressure to give 5-acetyl-N2-t-butoxycarbonyl-1-methylglycocyamidine asan oily substance. Without any further purifications, this oily residuewas used in the following reaction.

In the same manner, the following compounds were obtained.

5-acetyl-N² -t-butoxycarbonyl-3-methylglycocyamidine

5-acetyl-3-t-butoxycarbonyl-N² -methylglycocyamidine

5-acetyl-1,N² -di-t-butoxycarbonylglycocyamidine

(3) 100 ml of trifluoroacetic acid was added to the resulting productsas mentioned above. The solution was stirred for an hour at roomtemperature to remove the protecting group to give 5-acetyl1-methylglycocyamidine, which was used in the following reaction withoutany further purifications.

In the same manner, the following compounds were obtained.

5-acetyl-3-methylglycocyamidine

5-acetyl-N² -methylglycocyamidine

5-acetylglycocyamidine

(4) The solvent was distilled off under reduced pressure. 100 ml of 1Nhydrochloric acid was added to the residue and the reaction mixture wasstirred for 2 days at room temperature. The solution was concentrated todryness. The crude crystals were washed with ethyl acetate andrecrystallized from ethanol to give 8.1 g of5-hydroxy-1-methylglycocyamidine hydrochloride (Compound 1).

m.p.: 191 ° C. (decomposition)

Elementary Analysis: C₄ H₈ N₃ O₂ Cl

    ______________________________________                                                  C %        H %    N %                                               ______________________________________                                        Calculated  29.02        4.87   25.38                                         Found       29.10        4.82   25.70                                         ______________________________________                                    

MS (EI, 70eV): 129 (M⁺), 127, 101, 73, 56, 42

NMR(DMSO-d₆ /TMS): δ=3.01(3H,s), 5.13(1H,d,J=6Hz), 7.69(1H,d,J=6Hz),9.28(1H,s), 9.42(1H,s)

In the same manner, the following compounds were obtained.

5-hydroxy-3-methylglycocyamidine hydrochloride

(Compound 2)

m.p.: 186 ° C. (decomposition)

NMR(DMSO-d₆ /TMS): δ=3.07(3H,s), 5.35(1H,d,J=9Hz), 7.43(1H,d,J=9Hz),7.83(1H,br.s), 8.47(1H,br.s), 8.54(lH,br.s)

5-hydroxy-N² -methylglycocyamidine hydrochloride

(Compound 3)

m.p.: 172 ° C. (decomposition)

NMR(DMSO-d₆ /TMS): δ=2.92(3H,s), 5.30+5.36(1H,s), 7.39+7.54(1H,br.s),9.54+9.65(1H,br.s), 9.97+10.50(1H,br.s), 12.48(1H,br.s)

5-hydroxyglycocyamidine hydrochloride (Compound 4)

m.p.: 220 ° C. (decomposition)

NMR(DMSO-d₆ /TMS): δ=4.82(1H,d,J=7.8Hz), 6.21(1H,d,J=7.8Hz),7.07(1H,br.s), 7.64(1H,br.s), 7.83(1H,br.s)

It was observed that the compound 1 of the present invention wasincreasingly produced and accumulated in the body in patients sufferingfrom renal failure. It is very important for evaluating the diseasedstate to determine the compound 1 in the fluid such as serum orcerebrospinal fluid and the urine, particularly, the determination ofthe existence and the amount change of the compound in serum of renalfailure patients is very useful for diagnosis of renal failure, and sothat provides an easy diagnosis method. Therefore, the compounds of thepresent invention are useful as test reagents for diagnosis of renalfailure such as uremia, chronic nephritis or urinary obstruction.

What is claimed is:
 1. A glycocyamidine derivative having the formula(I) or a pharmaceutically acceptable salt thereof: ##STR5## wherein R₁,R₂ and R₃, which may be the same or different, is hydrogen or a loweralkyl group, and R is hydrogen or an acetyl group.
 2. A glycocyamidinederivative according to claim 1 wherein R₁ is a lower alkyl group.
 3. Aglycocyamidine derivative according to claim 2 wherein R₂, R₃ and R ishydrogen.
 4. A glycocyamidine derivative according to claim 3 wherein R₁is methyl group.